The present invention relates to a process cartridge.
Here, the process cartridge is a cartridge containing at least a developing roller as developing means and an electrophotographic photosensitive member as a unit, the cartridge being detachably mountable to a main assembly of an electrophotographic image forming apparatus.
The electrophotographic image forming apparatus is an apparatus in which an image is formed on a recording material (recording paper, textile or the like) using an electrophotographic image forming process, and includes an electrophotographic copying machine, an electrophotographic printer (a LED printer, laser beam printer and so on), an electrophotographic printer type facsimile machine, an electrophotographic word processor and the like.
In an electrophotographic image forming apparatus using an electrophotographic image forming process, a process cartridge is used that integrally contains an electrophotographic photosensitive member and process means actable on the electrophotographic photosensitive member, the process cartridge being detachably mountable to the main assembly of the electrophotographic image forming apparatus. With this process- cartridge type, the maintenance of the apparatus can be carried out in effect without service people. Therefore, the process cartridge type is widely used in the field of the electrophotographic image forming apparatus.
Such a process cartridge forms an image on recording material with toner. In the process cartridge, the developing roller of the developing means and the electrophotographic photosensitive member are coupled with other by gears.
During transportation of the process cartridge, the photosensitive drum is press-contacted to the spacer rollers at the end of portions of the developing roller.
And, the gear fixed coaxially to the photosensitive drum and the gear coaxially fixed to the developing roller are in a regular meshing engagement with each other. By impact or vibration imparted to the process cartridge during transportation, the gear teeth of the gears abut each other with a result of rotation of the photosensitive drum and the developing roller. If the directions of the rotations are all opposite from the directions during the image forming operation, the blow-out preventing sheet counter-directionally contacted to the peripheral surface of the developing roller may be turned over.
Accordingly, it is a principal object of the present invention to provide a process cartridge in which the developing roller is prevented from or suppressed in rotating in the direction opposite from the regular direction (the direction in which the developing roller rotates during the image formation operation), during the transportation of the process cartridge.
It is another object of the present invention to provide a process cartridge in which the toner leakage to the outside is effectively prevented.
According to an aspect of the present invention, there is provided a process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, comprising: an electrophotographic photosensitive drum; a drum gear provided at one longitudinal end of the photosensitive drum; a developing roller for developing with toner an electrostatic latent image formed on the photosensitive drum; a developing roller gear, provided at one longitudinal end of developing roller, for meshing engagement with the drum gear to transmit a driving force for rotating the developing roller from the drum gear; a cleaner container supporting the photosensitive drum; a toner developing container supporting developing roller; a coupling member for rotatably connecting the cleaner container and the toner developing container with each other; an urging member for urging the cleaner container and the toner developing container coupled by the coupling member in the direction of engagement of the drum gear and the developing roller gear with each other; a tape stuck continuously on the cleaner container and the toner developing container to maintain, against an urging force provided by the urging member, a state in which the drum gear developing roller gear are disengaged from each other or in which a back clearance between the drum gear and the developing roller gear is larger than that during image forming operation.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.